Moms-to-be are often bombarded with information about what happens to their bodies during labour and delivery, but many are surprised by what happens to their bodies afterwards. To help prevent post-childbirth surprises, here are the top five things most new moms don't know:

Postnatal bleeding can last for weeks–even if you had a C-section

"How much bleeding occurs after childbirth often comes as a surprise," says Dr. Marjorie Greenfield, an ob/gyn in Cleveland and author of The Working Woman's Pregnancy Book. "It can be like having a heavy period for two weeks and it's totally normal, even if you had a C-section."

Postnatal bleeding is caused by the placenta separating from where it was attached to the uterus and has nothing to do with the birth canal, which is why it affects all women after they deliver, says Dr. Greenfield. Bleeding can last for as long as six weeks and usually starts out bright red before fading to a pink or brown discharge called lochia, which eventually becomes a yellowish colour.

Many women are also surprised when they're told not to use tampons after giving birth, says Dr. Greenfield. But it's best to stock up on pads for at least six weeks because tampons can introduce bacteria to your still-healing uterus and may cause an infection. Although postnatal bleeding is perfectly normal, you should call your doctor if you experience extremely heavy bleeding that soaks a maxi pad within an hour, or if the bleeding includes large clots of blood.